A conventional combustible gas turbine engine includes a compressor section, a combustion section including a plurality of combustors, and a turbine section. Ambient air is compressed in the compressor section and conveyed to the combustors in the combustion section. The combustors combine the compressed air with a fuel and ignite the mixture creating combustion products defining hot working gases that flow in a turbulent manner and at a high velocity. The working gases are routed to the turbine section via a plurality of transition ducts. Within the turbine section are rows of stationary vane assemblies and rotating blade assemblies. The rotating blade assemblies are coupled to a turbine rotor. As the working gases expand through the turbine section, the working gases cause the blades assemblies, and therefore the turbine rotor, to rotate. The turbine rotor may be linked to an electric generator, wherein the rotation of the turbine rotor can be used to produce electricity in the generator.
The transition ducts are positioned adjacent to the combustors and route the working gases into the turbine section through turbine inlet structure associated with a first row vane assembly. Because the transition ducts and the turbine inlet structure are formed from different materials, they experience different amounts of thermal growth. That is, both the transition ducts and the turbine inlet structure may move radially, circumferentially, and/or axially relative to one another as a result of thermal growth of the respective components. Thus, seal assemblies are typically used in gas turbine engines between the transition ducts and the turbine inlet structure to minimize leakage between the working gases passing into the turbine section and cooling air, i.e., cold compressor discharge air, which is used to cool structure within the gas turbine engine.